What is the one line best for small mouth bass

There isn't a best line for smallmouth. It's all about what kind of tackle you like use & matching the line to what you are using. I like 10lb braid or 10lb mono for them but I fish for bigger smallies & and over rock. I have fished with 4-15lb mono and 10-20lb braid depending on tackle.

I use soft plastics and crank baits

10 lb YHB is hard to beat.

I think another aspect is the environment. For example in boat on a lake I would have a tendency to use lighter line then in a kayak on a river. For soft plastics I like a braid in the 10-30# range depending on spinning or casting. For crankbaits I like an 8-10# copolymer.

Thx for the info:)

There isn't a best line but with mono u can get away with anthing